A conventional automatic record medium player, e.g., a compact disc player for carrying out an automatic disc loading/unloading operation is constituted as shown in FIG. 1. In FIG. 1, a main chassis 11 is provided for supporting some elements as described below. A sub-chassis 12 with an L-shaped section is mounted on the main chassis 11. A motor support chassis 13 is provided over the sub-chassis 12. The motor support chassis 13 and the sub-chassis 12 hold a disc drive motor 14 therebetween. A driving shaft 14a of the disc drive motor 14 rotatably penetrates upward from the motor support chassis 13. A turntable 15 is mounted on the top end of the driving shaft 14a. Thus, the turntable 15 is driven by the disc drive motor 14.
A loading motor 16 is mounted on the sub-chassis 12. A driving shaft 16a of the loading motor 16 rotatably penetrates downward from the sub-chassis 12. A drive gear 17 is mounted on the top end of the driving shaft 16a. Thus, the drive gear 17 is driven by the loading motor 16.
The drive gear 17 is coupled to a disc lift 18 through first and second idler gears 19 and 20. The first and second idler gears 19 and 20 are rotatably mounted on the sub-chassis 12 by support pins 21 and 22, respectively. Both the support pins 21 and 22 extend from the sub-chassis 12. The drive gear 17 meshes with a large gear section 19a of the first idler gear 19. A small gear section 19b of the first idler gear 19 meshes with the second idler gear 20. The large gear section 19a and the small gear section 19b of the first idler gear 19 are coaxially made of one body.
The disc lift 18 comprises a lifting rod 23, a disc carriage 24, a travelling nut 25 and a lifting rod gear 26. The lifting rod 23 is rotatably supported on the main chassis 11 through a bearing 27. The lifting rod gear 26 is fixed to the lifting rod 23 coaxial thereto. The lifting rod gear 26 then meshes with the second idler gear 20. Thus, the lifting rod 23 is driven by the loading motor 16 through the drive gear 17, the first and second idler gears 19, 20 and the lifting rod gear 26, in turn.
The lifting rod 23 is provided with a feed screw 23a on the outer surface. The feed screw 23a extends along the axis of the lifting rod 23. The feed screw 23a of the lifting rod 23 screws into the travelling nut 25. The travelling nut 25 is fixed to the disc carriage 24. The disc carriage 24 is mounted to a guide member (not shown) slidable in the direction along the lifting rod 23. Thus, the disc carriage 24 moves in the direction along the lifting rod 23, when the lifting rod 23 is driven by the loading motor 16.
The rotation of the loading motor 16 changes in response to a loading phase or an unloading phase in the automatic disc loading operation. For example, the loading motor 16 rotates in a prescribed first direction during the loading phase. The loading motor 16 rotates in a second direction opposite to the first direction during the unloading phase. Thus, the disc carriage 24 travels downward, as shown by an arrow A in the drawing, during the loading phase. The disc carriage 24 travels upward, as shown by an arrow B in the drawing, during the unloading phase.
The disc carriage 24 is shaped as an almost rectangular plate. Further, the disc carriage 24 defines a round depression for carrying a disc 28 in the center of the rectangular plate and an opening around the center of the depression. The round depression has a diameter almost equal to the diameter of the disc 28 so that the disc 28 is placed in the correct position on the disc carriage 24. The opening allows the turntable 15 to penetrate the disc carriage 24 and to engage with the disc 28, when the disc carriage 24 moves downward. Further, the disc carriage 24 defines a slit for allowing an optical pickup to move in the radial direction of the turntable 15. The slit and the optical pickup are not shown in the drawing.
When the disc 28 is placed in the depression of the disc carriage 24, its center hole is positioned at the center of the turntable 15. Thus, the disc carriage 24 is moved downward when a disc loading operation is carried out. As a result, the disc 28 is placed on the turntable 15. The optical pickup is then able to trace an information track of the disc 28 placed on the turntable 15.
According to the conventional automatic loading compact disc player, at least two motors, e.g., the disc drive motor 14 and the loading motor 16, are necessary. Thus, the construction of the player becomes complicated.
Further, the disc player requires a relatively large space for accommodating the plurality of motors. The matter of space in the disc player may become a serious problem when miniturization of the size of the disc player is attempted. For example, a disc player for mounting in the dashboard of automobiles is limited in size to prescribed dimensions.
Furthermore, using a plurality of motors is expensive.